I was getting this warning message
warning: Missing argument 1 for system_clear_cache_submit(), called in My_website_path\sites\all\modules\admin_menu\admin_menu.inc on line 522 and defined in My_website_path\modules\system\system.admin.inc on line 1367.
since a while. I was feeling lazy to check the cause of it, all i have to do is to reload the home page of the drupal project.
Finally I fixed it by defining an empty array in the admin_menu.inc file:
$form_state = array();
$form_array = array();